1
 CAR/SAM RPM/WRC-2003 WP/XXCARS/SAM Regional
Preparatory Meeting for WRC-2003  AGENDA ITEM
2 Measures to address unauthorised use of and
Interference to the Aeronautical HF bands
(WRC-2003 Agenda Item 1.14)Presented by Jim
WellerSpectrum ManagerAirservices
AustraliaMEXICO CITY, 11 12 DECEMBER 2002
2
Introduction

• What is the problem?
• Is it still a problem?
• Background
• Progress
• What can WE do about it NOW?

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Sources of HF Interference
Extract from WRC-2000 Paper Doc 136 (USA)
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Sources of HF Interference
Extract from WRC-2000 Paper Doc 136 (USA)
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Is it still a problem?

• As of 2001 Australian Flight Information
  Service operators and pilots reported 3 major
  sources of Interference on the HF aeronautical
  mobile (R) service frequencies
•         Authorised co-channel voice
  transmissions
•         Unauthorised co-channel voice
  transmissions
•         Data transmissions

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Extract from Airservices Report on HF
Aeronautical Mobile (R) Services Interference
during the ITU Second Special Monitoring
Programme, 25 June 1 July 2001 (ITU Circular
letter (CR/147))
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Background

• WRC-2003 Agenda item 1.14
• ITU Resolution 207

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WRC-03 agenda item 1.14
to consider measures to address harmful
interference in the bands allocated to the
maritime mobile and aeronautical mobile (R)
services taking into account Resolutions 207
(Rev. WRC-2000) and 350 (WRC-2000), .
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ITU Resolution 207

• Measures to address unauthorized use of and
  interference to frequencies in the bands
  allocated to the maritime mobile service and to
  the aeronautical mobile (R) service
• The World Radiocommunication Conference
  (Istanbul, 2000),
• resolves to invite ITU-R and ITU-D, as
  appropriate
• to study possible technical and regulatory
  solutions to assist in the mitigation of
  interference
• to increase regional awareness of appropriate
  practices in order to help mitigate interference
  in the HF bands, especially on distress and
  safety channels
• 3 to report the results of the above studies to
  the next competent conference (ie WRC-2003),

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Resolution 207 (contd)
urges administrations 2 to make every effort to
identify and locate the source of any
unauthorized emission capable of endangering
human life or property and the safe and regular
conduct of aircraft operations, and to
communicate their findings to the
Radiocommunication Bureau 3 to participate in
the monitoring programmes that the
Radiocommunication Bureau may organize pursuant
to this Resolution 4 to make every effort to
prevent unauthorized transmissions in bands
allocated to the maritime mobile service and the
aeronautical mobile (R) service 5 to request
their competent authorities to take, within their
respective jurisdiction, such legislative or
regulatory measures which they consider necessary
or appropriate in order to prevent stations from
unauthorized use of distress and safety channels
or from operating in contravention of No. S23.2
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Progress

• Special ITU-R Monitoring Programme
• - Administrations and Aviation Authorities
  participated in Monitoring of HF Aeronautical
  frequencies as per ITU CR/147
• - 20-26 Nov 2000, 25 June 1 July 2001, 14 20
  Jan 2002
• - ITU Report expected by end of 2002
• Australian Aviation Study
• - Submitted as AMCP WGF7 WP/31 (Bangkok, Nov
  01)
• - Further discussion through APT WP4 Bulletin
  Board (BB) and Correspondence Group (CG)
• CPM Text - draft CPM text developed at AMCP
  WGF7 (Bangkok, Nov 01) - submitted at ITU-R
  WP8B (May 02) - adopted at CPM02-2 with input
  from SC02 and APT

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Proposed Solution (CPM Text)

• No suitable comprehensive technical solution has
  been found to eliminate interference.
• Enforcement of existing regulatory provisions
  and cooperative actions by administrations,
  together with
• Recommended Measures and Techniques to reduce
  interference
•         Alternative modulation methods
•         Passive and active/adaptive antenna
  systems
•         Channel barring
•         Regional Monitoring and DF        
  Transmission of Warning Messages
•         Education and Publicity

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(1) Alternative modulation methods

• Digital Modulation protocols (FSK, QPSK etc.) as
  a replacement for analogue SSB voice
  communications would reduce the effect of
  interference on communication.
• ICAO has adopted HF datalink (HFDL) packet data
  communication as part of the aeronautical
  telecommunications network (ATN) refer Annex
  10, Vol. III, Part I, Ch 11.
• Not a replacement but supplement for voice
  communications.
• Disadv The cost of implementing a replacement
  for voice communications system internationally
  in aircraft and at base stations.
• Disadv Does not remove interference from the
  channel.

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(2) Passive active/adaptive antenna systems

• Antenna is the most influential element in
  determining the performance of the HF radio
  system.
• Passive antenna Directivity, Takeoff angle
  (modes), Polarisation. eg Near Vertical Incidence
  Skywave (NVIS), Multi-modes
• Active antenna Beam shaping. Eg Phased arrays
• Antenna voting at antenna and/or location level.
• Adv Can be implemented country-by-country.
• Disadv Cost to implement may preclude uptake.
• Disadv Major benefit only to ground operator.

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(3) Channel barring of TX equipment

• Legislative action that requires HF radio
  equipment manufacturers to prevent users of their
  equipment from accessing aeronautical channels
  (through electronic barring) without proper
  authorisation.
• More practical for new equipment, but maybe
  retrospective with financial incentive for
  returned equipment (as part of education/promotion
  programme).
• New equipment have digital tuners so the
  modification required would be minimal.
• Allows Regulators to be pro-active on this issue
  without the high ongoing costs of policing.
• Benefits to both operators (pilots) and base
  stations (flight service) in the aeronautical and
  maritime services.

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(4) Regional Monitoring and DF

• Indirect mitigation technique
• Ability to ascertain the location of
  unauthorised users would enable regional
  authorities to assess the severity of the problem
  and to police it.
• Implementation of a comprehensive and effective
  HF Monitoring and Direction Finding Network would
  require cooperation and commitment from many
  Regional member states.
• System accuracy proportional to the number and
  geographic spread of monitoring stations.
• Airservices makes use of an Interference Report
  form (refer AMCP WGF/7 WP/31 attachment 3) to
  report harmful interference to the Regulator
  (ACA).

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(5) Transmission of warning messages

• Transmission of a warning message on the channel
  affected by persistent harmful interference.
• Airservices Broadcast tapes are in five
  languages (Bahasa Indonesian, Korean, Taiwanese,
  Japanese and Chinese).
• Australian Flight Information Service have a
  digital service integrated in consoles.
• Australian Communications Authority Monitoring
  Station (Quoin Ridge, Tasmania) reports that
  these tapes are very successful to clear
  frequency in short term.
• Long term effectiveness difficult to be
  assessed.
• Potential for interference to authorised users.

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(6) Education and Publicity

• Encourage and assist in regional education and
  publicity of the proper use of aeronautical
  radiocommunications spectrum.
• Encourage the establishment and support of
  closer international and regional liaison with
  national administrations (regulators) and
  aviation authorities.

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What can WE do about it NOW?

• Review ITU Report from Special Monitoring
  programme http//itu.int/brtpr/monitoring/index.ht
  ml
• Support the CPM text directly or via Regulators
  at WRC-2003
• Raise concern and encourage Regulators to enforce
  Radio Regulation.
• Countries adopt appropriate mitigation measures
  and techniques in consultation with ICAO.

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DISCUSSION AND FEEDBACK

• Questions??
• Contact jim.weller_at_airservices.gov.au